He has made himself the stooge, the mark, for every crazy blogger, political quack, racial theorist, foreign leader or nutcase peddling a story that he might repackage to his benefit as a tweet, an appointment, an executive order or a policy. He is a stranger to the concept of verification, the insistence on evidence and the standards of proof that apply in a courtroom or a medical lab — and that ought to prevail in the White House.

There have always been those who accept the intellectually bankrupt notion that people are entitled to invent their own facts — consider the “9/11 was an inside job” trope — but Trump’s ascent marks the first time that the culture of alternative reality has made its home at 1600 Pennsylvania Ave.

If Americans are unsure which Trump they have — the Machiavellian negotiator who lies to manipulate simpler minds, or one of those simpler minds himself — does it really matter? In either case he puts the nation in danger by undermining the role of truth in public discourse and policymaking, as well as the notion of truth being verifiable and mutually intelligible.

In the months ahead, Trump will bring his embrace of alternative facts on the nation’s behalf into talks with China, North Korea or any number of powers with interests counter to ours and that constitute an existential threat. At home, Trump now becomes the embodiment of the populist notion (with roots planted at least as deeply in the Left as the Right) that verifiable truth is merely a concept invented by fusty intellectuals, and that popular leaders can provide some equally valid substitute. We’ve seen people like that before, and we have a name for them: demagogues.

Our civilization is defined in part by the disciplines — science, law, journalism — that have developed systematic methods to arrive at the truth. Citizenship brings with it the obligation to engage in a similar process. Good citizens test assumptions, question leaders, argue details, research claims.

Investigate. Read. Write. Listen. Speak. Think. Be wary of those who disparage the investigators, the readers, the writers, the listeners, the speakers and the thinkers. Be suspicious of those who confuse reality with reality TV, and those who repeat falsehoods while insisting, against all evidence, that they are true. To defend freedom, demand fact.

It was no secret during the campaign that Donald Trump was a narcissist and a demagogue who used fear and dishonesty to appeal to the worst in American voters. The Times called him unprepared and unsuited for the job he was seeking, and said his election would be a “catastrophe.”

Still, nothing prepared us for the magnitude of this train wreck. Like millions of other Americans, we clung to a slim hope that the new president would turn out to be all noise and bluster, or that the people around him in the White House would act as a check on his worst instincts, or that he would be sobered and transformed by the awesome responsibilities of office.

Instead, seventy-some days in — and with about 1,400 to go before his term is completed — it is increasingly clear that those hopes were misplaced.

In a matter of weeks, President Trump has taken dozens of real-life steps that, if they are not reversed, will rip families apart, foul rivers and pollute the air, intensify the calamitous effects of climate change and profoundly weaken the system of American public education for all.

His attempt to de-insure millions of people who had finally received healthcare coverage and, along the way, enact a massive transfer of wealth from the poor to the rich has been put on hold for the moment. But he is proceeding with his efforts to defang the government’s regulatory agencies and bloat the Pentagon’s budget even as he supposedly retreats from the global stage.